Are you saying that cognition relies on something that Turing complete computation doesn't provide? Or are you saying that semiconductors won't scale to a point that will intersect with what would be necessary for cognition? Or the AI would need access to lots of robots/manufacturing in order to perform the basic science that would be necessary for evolutionary leaps. Or something else is a limiting factor?

It would have to be an AI trained with expertise in many fields before it could start to become a strong AI for sure... If we silo the information provided to each AI instance, and disallow them to communicate directly, we could probably prevent a strong AI. Without a wide range of experiences, I don't think a human-level AI would have the "imagination" to become a strong AI.